1. Field of the Invention
The invention relates generally to automotive steering columns, and more particularly to automotive steering columns having a steering lock mechanism.
2. Related Art
Modern day automobiles typically employ a steering lock mechanism to prevent the steering wheel of the automobile from turning without first rotating the keys in the ignition. Often, such lock mechanisms include a lock plate fixed on the steering shaft via mating splines near the upper end of the shaft and having a plurality of circumferentially spaced locking tabs. A lock bolt actuator, located forward of the lock plate, is operative to position a lock bolt between adjacent tabs to prevent rotation of the lock plate, and thus the steering shaft. Such a system is reliant on the strength of the splines to maintain a locked condition of the wheel under an applied torque load to the steering wheel. If the torque load exceeds the shear strength of the splines, the splines may yield, allowing unwanted rotation of the steering wheel.
Another drawback to the described steering lock mechanism is that the area immediately adjacent the end of the steering shaft, where the lock plate is located, is typically considered xe2x80x9cvaluable real estatexe2x80x9d in that not much area exists for other component parts that are typically located in this area. Today""s vehicles typically incorporate supplementary inflation restraint (SIR) systems having components located in this area. As such, the usable space in this area has become more limited for components such as the lock plates described above.
A steering lock mechanism constructed according to the present invention overcomes or greatly minimizes the above limitations of prior steering shaft lock devices.
A steering lock mechanism for a vehicle has an actuator movable between a first and second position. A lock bolt communicating with the actuator moves between a locked and unlocked position in response to the movement of the actuator between the first and second positions, respectively. A steering shaft rotatable about an axis for steering wheels of the vehicle has an upper end for supporting a hand wheel. A bolt engaging device is supported adjacent a lower end of the steering shaft. The bolt engaging device is in position to engage the lock bolt in response to movement of the lock bolt to the locked position to restrict rotation of the steering shaft about its axis and to disengage of the lock bolt in response to movement of the lock bolt to the unlocked position to restore unrestricted rotation of said steering shaft.
One advantage of this invention is that the lock bolt is located outside of the area considered valuable real estate, thereby reducing congestion in this area to allow the space to be used by other components.
Another advantage of this invention is that torque forces applied through the bolt engagement device will not cause damage between the device and the upper steering shaft.
Another advantage of this invention is that manufacturing costs are reduced and efficiencies are improved by providing a locking mechanism that can be universally applied across a variety of steering column lines.
Another advantage of this invention is that the forces on the components within the steering column are reduced, thus reducing the potential damage to the components.